Pub Date : 2025-01-15DOI: 10.1016/j.ijmecsci.2025.109937
Z.Z. He , C.L. Zhang , C.Z. Zhang , W.Q. Chen
We propose a dielectric metamaterial plate (DMP) like structure consisting of a pure dielectric plate and simple external L-C circuits utilizing the interaction between the flexoelectric-induced polarization field and the l-C circuits. For modeling and predicting wave propagation properties of flexural waves in the proposed DMP structures, we develop a two-dimensional (2D) mixed finite element method (M-FEM) incorporating flexoelectricity and external L-C circuits and also verify its accuracy with the corresponding analytical solutions. The unique wave propagation phenomena including bandgap tuning, wave localization and topological interface state in the proposed DMP structure are examined and manipulated through changing parameters of the electrode pairs and the connected L-C circuits. Numerical results show that altering the length of the electrode pairs and adjusting the connected L-C circuits can flexibly and effectively control wave propagation characteristics of flexural waves in the proposed DMP structures. This paper not only provides a new way for the design of mechanical metamaterials with programable wave properties but also lays the theoretical foundation for modeling multi-field coupling mechanical behaviors of DMP structures coupled with flexoelectricity and external L-C circuits.
{"title":"Programmable dielectric metamaterial plates via flexoelectricity and L-C circuits","authors":"Z.Z. He , C.L. Zhang , C.Z. Zhang , W.Q. Chen","doi":"10.1016/j.ijmecsci.2025.109937","DOIUrl":"10.1016/j.ijmecsci.2025.109937","url":null,"abstract":"<div><div>We propose a dielectric metamaterial plate (DMP) like structure consisting of a pure dielectric plate and simple external <em><span>L</span>-C</em> circuits utilizing the interaction between the flexoelectric-induced polarization field and the <em>l-C</em> circuits. For modeling and predicting wave propagation properties of flexural waves in the proposed DMP structures, we develop a two-dimensional (2D) mixed finite element method (M-FEM) incorporating flexoelectricity and external <em><span>L</span>-C</em> circuits and also verify its accuracy with the corresponding analytical solutions. The unique wave propagation phenomena including bandgap tuning, wave localization and topological interface state in the proposed DMP structure are examined and manipulated through changing parameters of the electrode pairs and the connected <em><span>L</span>-C</em> circuits. Numerical results show that altering the length of the electrode pairs and adjusting the connected <em><span>L</span>-C</em> circuits can flexibly and effectively control wave propagation characteristics of flexural waves in the proposed DMP structures. This paper not only provides a new way for the design of mechanical metamaterials with programable wave properties but also lays the theoretical foundation for modeling multi-field coupling mechanical behaviors of DMP structures coupled with flexoelectricity and external <em><span>L</span>-C</em> circuits.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109937"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143174478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.ijmecsci.2024.109911
Haoyu Hu , Chao Zhang , Rui Yue , Biao Hu , Shuai Chen
Whether adding tantalum (Ta) into tungsten (W) alloys can improve the ductility is controversial, which deserves the researches on the deformation mechanisms of W-Ta alloys. In this work, the machine learning potential (MLP) of W-Ta alloys with decent accuracy was developed first based on the dataset generated from ab-initio molecular dynamics (MD) method. Then, the effect of Ta concentration on the mechanical properties of W1-xTax (x = 0, 0.25, 0.5, and 0.75) alloys was investigated systemically by large-scale MD simulations with the developed MLP. Remarkably, the results indicate that adding Ta into W alloys decreases the yield strength and Young's modulus, and increases the bulk modulus/shear modulus ratio (B/G value) and Poisson's ratio. This trend demonstrates that the ductility of the W alloy increases with Ta concentration increasing. Further calculations reveal that the addition of Ta reduces the stacking fault energy of the W-Ta alloys. Last, the dislocation density and the total charge density of W-Ta alloys were explored to reveal the mechanism of ductility enhancement. Interestingly, the analyses unveil that the addition of Ta promotes the nucleation and proliferation of dislocations, thus facilitating the plastic deformation. This work provides useful insights on the effect of Ta on the ductility of W alloys, and guides the design of W-Ta alloys with superior mechanical properties.
{"title":"Unraveling ductility enhancement mechanisms in W-Ta alloys using machine-learning potential","authors":"Haoyu Hu , Chao Zhang , Rui Yue , Biao Hu , Shuai Chen","doi":"10.1016/j.ijmecsci.2024.109911","DOIUrl":"10.1016/j.ijmecsci.2024.109911","url":null,"abstract":"<div><div>Whether adding tantalum (Ta) into tungsten (W) alloys can improve the ductility is controversial, which deserves the researches on the deformation mechanisms of W-Ta alloys. In this work, the machine learning potential (MLP) of W-Ta alloys with decent accuracy was developed first based on the dataset generated from <em>ab</em>-<em>initio</em> molecular dynamics (MD) method. Then, the effect of Ta concentration on the mechanical properties of W<sub>1-</sub><em><sub>x</sub></em>Ta<em><sub>x</sub></em> (<em>x</em> = 0, 0.25, 0.5, and 0.75) alloys was investigated systemically by large-scale MD simulations with the developed MLP. Remarkably, the results indicate that adding Ta into W alloys decreases the yield strength and Young's modulus, and increases the bulk modulus/shear modulus ratio (B/G value) and Poisson's ratio. This trend demonstrates that the ductility of the W alloy increases with Ta concentration increasing. Further calculations reveal that the addition of Ta reduces the stacking fault energy of the W-Ta alloys. Last, the dislocation density and the total charge density of W-Ta alloys were explored to reveal the mechanism of ductility enhancement. Interestingly, the analyses unveil that the addition of Ta promotes the nucleation and proliferation of dislocations, thus facilitating the plastic deformation. This work provides useful insights on the effect of Ta on the ductility of W alloys, and guides the design of W-Ta alloys with superior mechanical properties.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109911"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143174823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The linear transformation has been successfully used to characterize the anisotropic ductile fracture, whereas the physical background of the transformed anisotropic stress state or the equivalent plastic strain becomes somewhat vague. This deficiency in the linear-transformation model might overlook the microscopic mechanisms of the anisotropic ductile fracture related to various stress states and loading direction. Therefore, this paper proposes an advanced linear-transformation-free anisotropic ductile fracture modeling framework that is dependent on stress triaxiality and the Lode angle, two state variables intimately related to microscopic fracture mechanisms. Notably, the model introduces the critical principal stress direction to account for the dependency on loading direction. The stress state variables and principal stress direction correspond to the geometry and sampling direction straightforwardly, which significantly facilitates the calibration of fracture parameters. Furthermore, compared to traditional linear-transformation-based anisotropic models, the proposed model is underpinned by a clear physical basis and accurately captures the relationships between triaxiality, Lode angle and material ductility with respect to varying loading directions. This model has been calibrated and validated based on the testing program on aluminum alloy 6061-T6 rolled plates under various stress states, considering both in-plane and out-of-plane anisotropies. The accurate prediction in terms of the softening initiation and failure modes for all testing cases demonstrate the validity of the proposed anisotropic ductile fracture model, as evidenced by the low averaged percentage of damage indicator at softening initiation at 4.6 %.
{"title":"Linear-transformation-free anisotropic ductile fracture model based on critical principal-stress-direction","authors":"Peihua Zhu , Weigang Zhao , Zhiyang Xie , Shitong Chen","doi":"10.1016/j.ijmecsci.2024.109914","DOIUrl":"10.1016/j.ijmecsci.2024.109914","url":null,"abstract":"<div><div>The linear transformation has been successfully used to characterize the anisotropic ductile fracture, whereas the physical background of the transformed anisotropic stress state or the equivalent plastic strain becomes somewhat vague. This deficiency in the linear-transformation model might overlook the microscopic mechanisms of the anisotropic ductile fracture related to various stress states and loading direction. Therefore, this paper proposes an advanced linear-transformation-free anisotropic ductile fracture modeling framework that is dependent on stress triaxiality and the Lode angle, two state variables intimately related to microscopic fracture mechanisms. Notably, the model introduces the critical principal stress direction to account for the dependency on loading direction. The stress state variables and principal stress direction correspond to the geometry and sampling direction straightforwardly, which significantly facilitates the calibration of fracture parameters. Furthermore, compared to traditional linear-transformation-based anisotropic models, the proposed model is underpinned by a clear physical basis and accurately captures the relationships between triaxiality, Lode angle and material ductility with respect to varying loading directions. This model has been calibrated and validated based on the testing program on aluminum alloy 6061-T6 rolled plates under various stress states, considering both in-plane and out-of-plane anisotropies. The accurate prediction in terms of the softening initiation and failure modes for all testing cases demonstrate the validity of the proposed anisotropic ductile fracture model, as evidenced by the low averaged percentage of damage indicator at softening initiation at 4.6 %.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109914"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.ijmecsci.2024.109913
Liming Huang , Hongyuan Wan , Quanfeng Han , Jianxiang Wang , Xin Yi
Additive manufacturing has enabled the creation of lattice structures with tunable properties, making them increasingly popular across various industries. However, their fatigue resistance remains a critical concern for long-term use. While contour scanning, a remelting technique in selective laser melting, improves surface quality and mechanical properties in tensile specimens, its effect on the fatigue behavior of as-built lattices remains underexplored. This study characterizes the manufacturing defects and intricate geometry of 316L skeletal gyroid lattice structures and investigates the impact of contour scanning on their compression-compression fatigue behavior through experimental and numerical approaches. The results show a significant improvement in high-cycle fatigue endurance due to contour scanning, attributed to enhanced surface smoothness. Cyclic ratcheting is identified as the dominant fatigue mechanism in both gyroid samples, with and without contour scanning. Additionally, fatigue life predictions based on finite element analysis, informed by experimental fatigue data and Basquin's equation, align well with experimental results. This work underscores the importance of contour scanning in enhancing the fatigue performance of lattice structures.
{"title":"Mitigating surface notches for enhanced fatigue performance of metallic gyroid structures via contour scanning","authors":"Liming Huang , Hongyuan Wan , Quanfeng Han , Jianxiang Wang , Xin Yi","doi":"10.1016/j.ijmecsci.2024.109913","DOIUrl":"10.1016/j.ijmecsci.2024.109913","url":null,"abstract":"<div><div>Additive manufacturing has enabled the creation of lattice structures with tunable properties, making them increasingly popular across various industries. However, their fatigue resistance remains a critical concern for long-term use. While contour scanning, a remelting technique in selective laser melting, improves surface quality and mechanical properties in tensile specimens, its effect on the fatigue behavior of as-built lattices remains underexplored. This study characterizes the manufacturing defects and intricate geometry of 316L skeletal gyroid lattice structures and investigates the impact of contour scanning on their compression-compression fatigue behavior through experimental and numerical approaches. The results show a significant improvement in high-cycle fatigue endurance due to contour scanning, attributed to enhanced surface smoothness. Cyclic ratcheting is identified as the dominant fatigue mechanism in both gyroid samples, with and without contour scanning. Additionally, fatigue life predictions based on finite element analysis, informed by experimental fatigue data and Basquin's equation, align well with experimental results. This work underscores the importance of contour scanning in enhancing the fatigue performance of lattice structures.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109913"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.ijmecsci.2024.109873
Yongfeng Zhang , Ziyuan Zhu , Zhehao Sheng , Yinzhi He , Gang Wang
This paper delves into the vibration and acoustic radiation properties of a metamaterial plate integrated with grouped local resonators (GLRs). The GLRs, consisting of multiple spring-mass resonators arranged in various configurations such as series, parallel, and periodic arrangements, are shown to significantly influence the structural performance of the plate. An advanced Fourier series is implemented to articulate the displacement functions and surface acoustic pressure of the plate. By utilizing the energy principle, a vibro-acoustic coupling model is developed to describe the interaction between the metamaterial plate and the external acoustic field. The theoretical framework is rigorously validated against finite element method simulations, yielding highly congruent results. The local resonance bandgap behavior is explored, and the results reveal that the arrangement and connection strategy of the GLRs determine the stopband characteristics. Multiple resonators connected in series lead to an increased number of stopbands and more pronounced attenuation valleys, whereas multiple resonators connected in parallel or arranged in a periodic array result in an unchanged number of stopbands but a significantly wider stopband bandwidth. Furthermore, transmission characteristic assessments substantiate the vibration dampening efficacy of GLRs, and the marked suppressions in flexural wave propagation are demonstrated within the multiple merged bandgaps. These insights advance the comprehension of localized resonance phenomena in metamaterials and inform the development of sophisticated noise and vibration control strategies.
{"title":"Vibro-acoustic suppression of metamaterial plates in multi-bandgaps","authors":"Yongfeng Zhang , Ziyuan Zhu , Zhehao Sheng , Yinzhi He , Gang Wang","doi":"10.1016/j.ijmecsci.2024.109873","DOIUrl":"10.1016/j.ijmecsci.2024.109873","url":null,"abstract":"<div><div>This paper delves into the vibration and acoustic radiation properties of a metamaterial plate integrated with grouped local resonators (GLRs). The GLRs, consisting of multiple spring-mass resonators arranged in various configurations such as series, parallel, and periodic arrangements, are shown to significantly influence the structural performance of the plate. An advanced Fourier series is implemented to articulate the displacement functions and surface acoustic pressure of the plate. By utilizing the energy principle, a vibro-acoustic coupling model is developed to describe the interaction between the metamaterial plate and the external acoustic field. The theoretical framework is rigorously validated against finite element method simulations, yielding highly congruent results. The local resonance bandgap behavior is explored, and the results reveal that the arrangement and connection strategy of the GLRs determine the stopband characteristics. Multiple resonators connected in series lead to an increased number of stopbands and more pronounced attenuation valleys, whereas multiple resonators connected in parallel or arranged in a periodic array result in an unchanged number of stopbands but a significantly wider stopband bandwidth. Furthermore, transmission characteristic assessments substantiate the vibration dampening efficacy of GLRs, and the marked suppressions in flexural wave propagation are demonstrated within the multiple merged bandgaps. These insights advance the comprehension of localized resonance phenomena in metamaterials and inform the development of sophisticated noise and vibration control strategies.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109873"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent advancements have identified orbital angular momentum (OAM) as a promising multiplexing strategy leveraging vortex beams to significantly enhance communication channel capacity. However, existing OAM signal demultiplexing methods, including active scanning and passive resonant techniques, encounter limitations such as reduced data transmission rates and the reliance on bulky, inefficient systems. In this work, we utilize gradient metamaterial Luneburg lens as a transformation medium to convert two-dimensional (2D) vortex beams into transmitted beams oriented in multiple directions. This approach not only improves system efficiency but also simplifies the OAM multiplexing framework. Through analysis, simulation and experiments, we verify the fast and broadband working properties of Luneburg lens constructed by non-resonant metamaterial unit cell. Additionally, by applying the coordinate transformation method, we further expand the beam separation angles achievable with the metamaterial lens. Notably, the vortex-based beamforming strategy also proves effective for multi-beam Luneburg lenses. Our work introduces a streamlined and efficient strategy for vortex detection and beam scanning, paving the way for advancements in high-speed, high-capacity acoustic communication systems and on-chip signal detection technologies.
{"title":"Acoustic metamaterial lens for two-dimensional vortex beamforming and perception","authors":"Yangyang Zhou , Yuhang Yin , Pengfei Zhao , Qilin Duan , Zhibin Zhang , Zhanlei Hao , Shan Zhu , Weihen Shao , Huanyang Chen","doi":"10.1016/j.ijmecsci.2024.109884","DOIUrl":"10.1016/j.ijmecsci.2024.109884","url":null,"abstract":"<div><div>Recent advancements have identified orbital angular momentum (OAM) as a promising multiplexing strategy leveraging vortex beams to significantly enhance communication channel capacity. However, existing OAM signal demultiplexing methods, including active scanning and passive resonant techniques, encounter limitations such as reduced data transmission rates and the reliance on bulky, inefficient systems. In this work, we utilize gradient metamaterial Luneburg lens as a transformation medium to convert two-dimensional (2D) vortex beams into transmitted beams oriented in multiple directions. This approach not only improves system efficiency but also simplifies the OAM multiplexing framework. Through analysis, simulation and experiments, we verify the fast and broadband working properties of Luneburg lens constructed by non-resonant metamaterial unit cell. Additionally, by applying the coordinate transformation method, we further expand the beam separation angles achievable with the metamaterial lens. Notably, the vortex-based beamforming strategy also proves effective for multi-beam Luneburg lenses. Our work introduces a streamlined and efficient strategy for vortex detection and beam scanning, paving the way for advancements in high-speed, high-capacity acoustic communication systems and on-chip signal detection technologies.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109884"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intergranular stress corrosion cracking (IGSCC) occurs in polycrystalline alloys, and this process is inherently stochastic. This study proposed a new approach to predict the service life of a component subjected to IGSCC considering the scatter of its processes due to microstructural inhomogeneity. First, the crack initiation, growth, and coalescence in IGSCC were stochastically modeled considering the influence of microstructural inhomogeneity on cracking behavior. Then, a time-evolution simulation was developed based on the models. In this simulation, the time and crack length were described using probability density functions. Hence, once a crack length reaches a certain critical value, a cumulative distribution function of the time to failure is obtained, which reveals the service life due to IGSCC. The developed simulation was applied to IGSCC of type 304 stainless steel in a simulated boiling water reactor environment. The simulation successfully reproduced the crack initiation event after the incubation period followed by repeated crack growth and coalescence events, which were characteristic of the entire IGSCC process, and the results agreed with those of another simulation that well reproduced previous experimental results. Furthermore, the critical crack was set at 5 mm long, and the service life distribution was obtained from a single calculation. The developed simulation based on the stochastic models is a sophisticated approach to predict the service life of a component considering crack initiation, growth, and coalescence. Hence, it is expected that the simulation contributes to ensuring long-term structural integrity.
{"title":"Stochastic model for intergranular stress corrosion cracking of stainless steel","authors":"Tomoyuki Fujii, Yuki Takeichi, Yoshinobu Shimamura","doi":"10.1016/j.ijmecsci.2024.109888","DOIUrl":"10.1016/j.ijmecsci.2024.109888","url":null,"abstract":"<div><div>Intergranular stress corrosion cracking (IGSCC) occurs in polycrystalline alloys, and this process is inherently stochastic. This study proposed a new approach to predict the service life of a component subjected to IGSCC considering the scatter of its processes due to microstructural inhomogeneity. First, the crack initiation, growth, and coalescence in IGSCC were stochastically modeled considering the influence of microstructural inhomogeneity on cracking behavior. Then, a time-evolution simulation was developed based on the models. In this simulation, the time and crack length were described using probability density functions. Hence, once a crack length reaches a certain critical value, a cumulative distribution function of the time to failure is obtained, which reveals the service life due to IGSCC. The developed simulation was applied to IGSCC of type 304 stainless steel in a simulated boiling water reactor environment. The simulation successfully reproduced the crack initiation event after the incubation period followed by repeated crack growth and coalescence events, which were characteristic of the entire IGSCC process, and the results agreed with those of another simulation that well reproduced previous experimental results. Furthermore, the critical crack was set at 5 mm long, and the service life distribution was obtained from a single calculation. The developed simulation based on the stochastic models is a sophisticated approach to predict the service life of a component considering crack initiation, growth, and coalescence. Hence, it is expected that the simulation contributes to ensuring long-term structural integrity.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109888"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.ijmecsci.2024.109899
Srinivasagan M. , Khirupa Sagar R. , Mahesh A. , Arun Krishna B.J. , Jayabal K.
Electromechanically coupled ferroelectric materials exhibit complex nonlinear behaviour under higher magnitudes of mechanical and electrical loading owing to their microscopic domain switching phenomenon. The presence of pre-cracks in the polycrystalline ferroelectrics intensifies the localized electric fields and mechanical stresses. In this paper, a micromechanical model combined with the scaled boundary finite element method (SBFEM) explores domain switching near the crack tip under cyclic electric fields and mechanical stresses. The solution for stress at the singularity near the crack tip is realized through SBFEM. A naturally evolving Voronoi polygonal tessellation is employed to mimic the microstructure of a typical polycrystalline ferroelectric material where each ferroelectric grain is represented by a Voronoi polygon. The dynamic crack propagation across grains under electrical or combined mechanical loading is predicted by introducing a novel re-meshing technique. The fracture parameters evaluated through the proposed method are validated by their close correspondence with the experimental compact tension test and three-point bend test results from the literature.
{"title":"Domain switching effects on crack propagation in ferroelectrics through SBFEM","authors":"Srinivasagan M. , Khirupa Sagar R. , Mahesh A. , Arun Krishna B.J. , Jayabal K.","doi":"10.1016/j.ijmecsci.2024.109899","DOIUrl":"10.1016/j.ijmecsci.2024.109899","url":null,"abstract":"<div><div>Electromechanically coupled ferroelectric materials exhibit complex nonlinear behaviour under higher magnitudes of mechanical and electrical loading owing to their microscopic domain switching phenomenon. The presence of pre-cracks in the polycrystalline ferroelectrics intensifies the localized electric fields and mechanical stresses. In this paper, a micromechanical model combined with the scaled boundary finite element method (SBFEM) explores domain switching near the crack tip under cyclic electric fields and mechanical stresses. The solution for stress at the singularity near the crack tip is realized through SBFEM. A naturally evolving Voronoi polygonal tessellation is employed to mimic the microstructure of a typical polycrystalline ferroelectric material where each ferroelectric grain is represented by a Voronoi polygon. The dynamic crack propagation across grains under electrical or combined mechanical loading is predicted by introducing a novel re-meshing technique. The fracture parameters evaluated through the proposed method are validated by their close correspondence with the experimental compact tension test and three-point bend test results from the literature.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109899"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143174822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.ijmecsci.2024.109905
Tom Fisher , Zafer Kazancı , José Humberto S. Almeida Jr.
This study explores the high-velocity impact response of 3D-printed composite mechanical metamaterials through a combination of experimental testing and numerical simulations. Auxetic structures demonstrated a marked reduction in transmitted force and an extended force duration, both of which are advantageous for mitigating impact-related injuries. Specifically, the double arrowhead auxetic geometry reduced the transmitted force by 44% compared to conventional hexagonal structures, albeit at the cost of 17% greater deformation. Novel hybrid designs, integrating auxetic and conventional geometries, achieved a decoupled control of deformation and force responses. For instance, a re-entrant auxetic structure on the impact face, transitioning into a hexagonal configuration, led to a 10% increase in deformation compared to the reverse orientation while maintaining a similar transmitted force. Additionally, a comprehensive parametric study was conducted to examine the influence of cell size and relative density on the overall impact performance of these metamaterials.
{"title":"High-velocity impact response of 3D-printed composite mechanical metamaterials","authors":"Tom Fisher , Zafer Kazancı , José Humberto S. Almeida Jr.","doi":"10.1016/j.ijmecsci.2024.109905","DOIUrl":"10.1016/j.ijmecsci.2024.109905","url":null,"abstract":"<div><div>This study explores the high-velocity impact response of 3D-printed composite mechanical metamaterials through a combination of experimental testing and numerical simulations. Auxetic structures demonstrated a marked reduction in transmitted force and an extended force duration, both of which are advantageous for mitigating impact-related injuries. Specifically, the double arrowhead auxetic geometry reduced the transmitted force by 44% compared to conventional hexagonal structures, albeit at the cost of 17% greater deformation. Novel hybrid designs, integrating auxetic and conventional geometries, achieved a decoupled control of deformation and force responses. For instance, a re-entrant auxetic structure on the impact face, transitioning into a hexagonal configuration, led to a 10% increase in deformation compared to the reverse orientation while maintaining a similar transmitted force. Additionally, a comprehensive parametric study was conducted to examine the influence of cell size and relative density on the overall impact performance of these metamaterials.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109905"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.ijmecsci.2024.109907
Zhi Zhang , Bo Song , Lei Zhang , Ruxuan Fang , Xiaobo Wang , Yonggang Yao , Gang Wu , Qiaojiao Li , Yusheng Shi
Lightweight metamaterials with high strength and superior heat insulation are crucial for hypersonic aircraft to resist mechanical and thermal shock under ultra-high speed conditions. However, an inverted relationship between mechanical properties and heat insulation leads to difficulties in their synergy improvement by controlling relative density. Therefore, innovative design of metamaterials for mechanical properties, heat insulation, and their successful fabrication are paramount, but often laborious because of the vast design space, associated complex mechanical-thermal physical models with spatial configuration, and their complex configuration with micron size. This work proposed a node optimization strategy for mechanical-heat insulation synergy improvement. Taking the previous bionic polyhedron metamaterial (BPM) imitated pomelo peel as an example, the node-optimized octahedron metamaterial (OCM) fabricated by laser powder bed fusion (LPBF) achieved superior heat insulation and high strength. Based on experiments and numerical simulations, the OCM with a unit cell size of 3 mm (OCM3) had equivalent thermal conductivity (ETC) of 0.72 W/(m·K) and 2.19 W/(m·K) at room temperature and 600 °C with 8 % relative density, respectively, its heat-shielding index was 77 % at the load plate with 370 °C in natural convection. Furthermore, the OCM3’s strength and Young's modulus were 23.71±0.75 MPa and 981.44±19.44 MPa at room temperature; At 600 °C, its strength and Young's modulus were 12.52±0.82 MPa and 376.97±12.78 MPa, respectively. The above finding will guide the design and optimization of metamaterials with high strength and exceptional heat insulation.
{"title":"A node-optimized metamaterial with high mechanical properties and heat insulation","authors":"Zhi Zhang , Bo Song , Lei Zhang , Ruxuan Fang , Xiaobo Wang , Yonggang Yao , Gang Wu , Qiaojiao Li , Yusheng Shi","doi":"10.1016/j.ijmecsci.2024.109907","DOIUrl":"10.1016/j.ijmecsci.2024.109907","url":null,"abstract":"<div><div>Lightweight metamaterials with high strength and superior heat insulation are crucial for hypersonic aircraft to resist mechanical and thermal shock under ultra-high speed conditions. However, an inverted relationship between mechanical properties and heat insulation leads to difficulties in their synergy improvement by controlling relative density. Therefore, innovative design of metamaterials for mechanical properties, heat insulation, and their successful fabrication are paramount, but often laborious because of the vast design space, associated complex mechanical-thermal physical models with spatial configuration, and their complex configuration with micron size. This work proposed a node optimization strategy for mechanical-heat insulation synergy improvement. Taking the previous bionic polyhedron metamaterial (BPM) imitated pomelo peel as an example, the node-optimized octahedron metamaterial (OCM) fabricated by laser powder bed fusion (LPBF) achieved superior heat insulation and high strength. Based on experiments and numerical simulations, the OCM with a unit cell size of 3 mm (OCM3) had equivalent thermal conductivity (ETC) of 0.72 W/(m·K) and 2.19 W/(m·K) at room temperature and 600 °C with 8 % relative density, respectively, its heat-shielding index was 77 % at the load plate with 370 °C in natural convection. Furthermore, the OCM3’s strength and Young's modulus were 23.71±0.75 MPa and 981.44±19.44 MPa at room temperature; At 600 °C, its strength and Young's modulus were 12.52±0.82 MPa and 376.97±12.78 MPa, respectively. The above finding will guide the design and optimization of metamaterials with high strength and exceptional heat insulation.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109907"},"PeriodicalIF":7.1,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号